In recent years, with the decreasing size and increasing performance of electronic devices, the increases in density and in the number of layers of electronic circuit boards for use in the electronic devices have taken place. For the increase in the number of layers of such electronic circuit boards, there is a requirement for smoothness of the surface of a laminated body obtained by laminating a resin film to a substrate having protruding and recessed portions. An example of a laminating apparatus which meets such a requirement is disclosed in Patent Literature 1. In this apparatus, a resin film made of a thermosetting resin composition or a photosensitive resin composition and a substrate are accommodated in one out of two enclosed spaces divided by a flexible sheet made of an expansive material. After the pressure in both of the aforementioned two divided enclosed spaces is reduced, the pressure in only the other enclosed space in which the resin film and the substrate are not accommodated is brought back to normal pressure or further increased to expand the flexible sheet made of the expansive material toward the pressure-reduced enclosed space (the enclosed space in which the resin film and the substrate are accommodated). The expanded flexible sheet applies pressure equally to the resin film and the substrate. Thus, the apparatus laminates the resin film and the substrate together. According to this apparatus, the aforementioned flexible sheet is expanded like a balloon by a difference in air pressure between the two enclosed spaces divided by the aforementioned flexible sheet made of the expansive material, so that part of the flexible sheet which contacts the substrate is deformed along the protruding and recessed portions of the substrate. In that state, pressure is applied to the resin film and the substrate. Thus, even when the substrate has protruding and recessed portions, this apparatus is capable of bringing the resin film into intimate contact with the protruding and recessed portions of the substrate.